CN219625672U - An online monitoring device for grounding status of traction power supply equipment - Google Patents

Abstract

The utility model discloses an on-line monitoring device for the grounding state of traction power supply equipment, comprising: a data acquisition unit, a calculation evaluation unit and an AC/DC excitation unit, the data acquisition unit is respectively connected with the grounding down conductor and the calculation evaluation unit, and the measured power equipment The grounding down-conductor is connected to the grounding grid, the AC/DC excitation unit, and the AC-DC excitation unit is connected to the grounding down-conductor to generate a DC signal or an AC current test signal different from the power frequency; when the AC/DC excitation unit generates a different When the AC current test signal of power frequency is used, the data acquisition unit is used to obtain the AC potential data of the grounding down conductor, and when the AC and DC excitation unit generates a DC signal, the data acquisition unit is used to obtain the DC potential data of the grounding down conductor; the monitoring device , By manually switching the excitation (DC or AC), the monitoring of equipment grounding resistance and the diagnosis of grounding grid corrosion are realized, providing a huge support for the monitoring of grounding grid operation status.

Description

An online monitoring device for grounding status of traction power supply equipment

technical field

The utility model relates to the technical field of equipment grounding state monitoring, in particular to an online monitoring device for traction power supply equipment grounding state.

Background technique

The traction substation is the core facility of the electrified railway. In order to ensure the safe operation of the railway and the safety of personnel, many electrical equipment including the traction transformer have been grounded for lightning protection. important factor in operation. Since the traction power supply system uses rails and the earth as the main return path, a large traction return current flows through the grounding system of the traction substation during normal operation. The grounding grid of traction substations in my country generally uses ordinary steel as the grounding conductor. In recent years, galvanized steel has also been used to improve anti-corrosion performance. However, due to the limitations of on-site construction conditions, soil corrosion, and electrochemical corrosion caused by traction ground backflow, severe corrosion will generally occur after 8 to 10 years of operation, resulting in a greatly reduced grounding performance, which seriously threatens the safety of equipment and personnel.

For a long time, there is no effective detection or evaluation method for the operation status of the traction substation grounding system on the railway, especially for the detection of grounding grid corrosion, disconnection and other faults, the method of power failure sampling and excavation is mainly used. This method has blindness, heavy workload, slow speed, and is limited by field operating conditions, so it cannot accurately judge breakpoints and corroded conductors. At the same time, this method will cause a long-term power outage in the traction substation, which will affect the normal operation of the electrified railway.

In the Chinese patent application CN107290592A, a grounding network resistance online monitoring system is disclosed, which uses high-power different-frequency equipment to stimulate the loop current between the ground network under test and the current electrode, and uses the data acquisition unit to synchronously collect the measured power equipment and voltage. The voltage waveform between the poles is calculated by the filter analysis unit to calculate the different frequency voltage difference between each device and the zero potential, so as to calculate the grounding resistance of each device. However, when the conductor of the ground grid is corroded or even breaks, the grounding resistance may still be normal. Therefore, the system cannot realize the detection of conductor corrosion or even a breakpoint. After the grounding resistance is found to be unqualified or an accident is caused, a large-scale excavation is performed to find the breakpoint or The corrosion section is relatively blind, with a large workload, and also affects the operation of the power system.

Utility model content

In view of the above problems, the inventor provides an online monitoring device for the grounding state of traction power supply equipment. According to the actual circuit environment and requirements of the site, by switching the AC/DC power supply as the input of the system excitation (current test signal) to the grounding network of the traction station Inject corresponding incentives to realize the monitoring of grounding resistance of each equipment and the corrosion detection data of the steel used for lightning protection grounding of the grounding grid, so as to confirm the condition of the lightning protection grounding return path of the traction substation, and ensure the safe operation of the electrified railway and the safety of personnel.

Specifically, the utility model is achieved in this way:

An online monitoring device for grounding status of traction power supply equipment, comprising:

data acquisition unit;

A calculation and evaluation unit, the data acquisition unit is respectively connected to the grounding down-conductor and the calculation and evaluation unit, and the electric equipment under test is connected to the grounding grid through the grounding down-conductor;

An AC/DC excitation unit, the AC/DC excitation unit is connected to the grounding down conductor, and is used to generate a DC signal or an AC current test signal different from the power frequency;

When the AC and DC excitation unit generates an AC current test signal different from the power frequency, the data acquisition unit is used to obtain the AC potential data of the grounding down conductor, and transmit the AC potential data of the grounding down conductor to the calculation and evaluation unit;

When the AC/DC excitation unit generates a DC signal, the data acquisition unit is used to obtain the DC potential data of the grounded down conductor, and transmit the DC potential data of the grounded down conductor to the calculation and evaluation unit.

Further, the AC/DC excitation unit includes:

DC power supply;

Frequency conversion AC power supply;

Dual power switch, connected with DC power supply and variable frequency AC power supply, for power switching;

The current limiting resistor is connected in series with the dual power switch.

Further, the calculation evaluation unit includes:

A data processing module connected to the data acquisition unit;

The display screen is connected with the data processing module and is used for displaying measured parameters.

Further, the data acquisition unit is connected to the branch of the ground grid through the clamp, and is connected to the calculation and evaluation unit for data.

Further, the data collection unit is a multi-channel data collection unit, each channel collects the grounding downconductor potential data of a branch, and the data collection unit is wirelessly connected to the calculation and evaluation unit.

Further, the data collection unit includes 16 data monitoring terminals and 4 GND terminals, which can realize the collection of 16 electrical quantity signals.

Further, the online monitoring device for the grounding state of the traction power supply equipment further includes a box body, and the AC/DC excitation unit and the calculation evaluation unit are integrated in the box body.

Working principle of the utility model:

When monitoring the resistance of the grounding grid, the current test signal different from the power frequency is generated by the variable frequency AC power supply, and the loop current is excited between the ground grid under test and the current pole, and the data acquisition unit is used to collect the voltage between the equipment under test and the voltage pole. Voltage waveform, calculate the different frequency voltage difference between each equipment and zero potential through the data processing module, thereby calculate the grounding resistance of each equipment, obtain the basic grounding grid resistance monitoring, and realize the confirmation of the lightning protection grounding return circulation of the traction substation real-time road conditions.

When conducting ground grid conductor corrosion and breakpoint detection, a DC power supply is generated by a variable frequency AC power supply to detect the resistance value of the ground grid branch under test. When the inspector finds that the detected resistance value is compared with the original resistance value of the branch If it becomes larger, it can be judged that there is corrosion or fracture in the branch.

Compared with the prior art, the utility model has the beneficial effects:

(1) The online monitoring device for the grounding status of traction power supply equipment provided by this application can not only use AC excitation to measure grounding characteristic parameters, but also use DC excitation to quantify and identify the corrosion state of the grounding grid, providing a huge support for monitoring the operating status of the grounding grid .

(2) Switch between AC and DC power sources by manually controlling the switch to generate DC signals or AC current test signals different from power frequency, and the operation is simple and convenient.

Description of drawings

Fig. 1 is the schematic diagram of the principle of the online monitoring device for the grounding state of the traction power supply equipment in the present application;

Fig. 2 is a schematic diagram of the use state of the traction power supply equipment grounding state online monitoring device in embodiment 1;

Fig. 3 is a partial enlarged view of place A in Fig. 2;

Fig. 4 is a structural block diagram of the online monitoring device for the grounding state of the traction power supply equipment in Embodiment 1;

Fig. 5 is the structural representation of the AC/DC excitation unit in Embodiment 1;

Fig. 6 is the terminal arrangement diagram of the data acquisition unit in embodiment 1;

Fig. 7 is a partial enlarged view of place B in Fig. 2;

Fig. 8 is a schematic diagram of the usage state of the online monitoring device for the grounding state of traction power supply equipment in Embodiment 2.

Reference signs:

1-AC/DC excitation unit; 11-adjusting knob; 2-data acquisition unit; 3-calculation and evaluation unit; 31-display screen; 32-data processing module; 4-grounding grid; 41-grounding downconductor; 5-box Body; 6-wire; 61-wiring clamp.

Detailed ways

The utility model will be described in further detail below through specific embodiments in conjunction with the accompanying drawings.

The grounding grid is mostly flat steel, angle steel or steel pipes, which are criss-crossed in a rectangular network. The criss-crossing points are nodes, and the grounding down-conductors are mostly connected to the nodes. There is a branch between the nodes, and several branches are combined to form a grounding network. .

Example 1

As shown in Figures 1-5, this embodiment provides an online monitoring device for the grounding state of traction power supply equipment, including: AC and DC excitation unit 1, data acquisition unit 2 and calculation and evaluation unit 3, AC and DC excitation unit 1 and calculation and evaluation unit The unit 3 is integrated in the box body 5, and the box body 5 is provided with a wiring interface. The AC and DC excitation unit 1 is connected to the grounding down conductor 41 through the wiring interface and the wire 6. One end of the grounding down conductor 41 is connected to the electrical equipment, and the other end Connected with the grounding grid 4, the AC/DC excitation unit 1 injects corresponding excitation into the grounding grid 4 of the traction station to measure grounding characteristic parameters. In this embodiment, the data collection unit 2 is a voltage collector, which is connected to the ground downconductor 41 through a wire 6 for collecting voltage values. Since the grounding down conductor 41 is mostly flat steel, in order to facilitate the connection between the wire 6 and the grounding down conductor 41, the end of the wire 6 is provided with a clamp 61, and the connection between the wire 6 and the grounding conductor can be realized by using the clamp 61. Quick connect for downline 41. The data acquisition unit 2 is connected to the box body 5 through the data interface. After collecting the voltage value, the voltage value is fed back to the calculation and evaluation unit 3, and the calculation and evaluation unit 3 calculates the resistance value according to the existing algorithm.

Specifically, as shown in FIG. 5 , the AC/DC excitation unit 1 includes a DC power supply DC, a variable frequency AC power supply AC, a dual power supply switch K, and a current limiting resistor R. AC switching. They are respectively connected with any two grounding down conductors 41 to form a loop.

When monitoring the grounding resistance of electrical equipment, switch to the variable frequency AC power supply AC, and adjust the magnitude of the AC current test signal input by the variable frequency AC power supply AC through the adjustment knob 11 according to the actual circuit environment and requirements on site. At this time, the measured by the data acquisition unit 2 It is the voltage waveform between each electric device under test and the voltage pole. The calculation and evaluation unit 3 calculates the different frequency voltage difference between each electric device under test and zero potential, thereby calculating the grounding resistance of each electric device under test.

When diagnosing the corrosion of the ground grid, switch to the direct current power supply DC, and what the data acquisition unit 2 measures at this time is the voltage value of each branch circuit under test. The grounding grid corrosion diagnostic equations are:

The relationship between the node voltage U _n and the branch resistance R _j is obtained as:

Among them, the partial conductance of the branch admittance to the jth branch resistance is:

The embedded algorithm in the data processing solver to solve the multiplier of branch resistance is composed of CPLEX solver, microprocessing method, PSO algorithm and so on. The theoretical equations of each algorithm are as follows:

(1) CPLEX solver

Take the equation (1) △ U _{accessible node} = V △ L _n as the solution equation, satisfy the constraint condition (4), take the minimum of (5) as the objective function, know the potential and sensitivity matrix of the accessible node, and find the branch multiplier of resistance.

△L _n ≥ 0, n = 1,2,...b (4)

min||U _es -U _et || ₂ (5)

(2) micro-processing method

The diagnostic model is preprocessed by microprocessing method, and the nonlinear model is piecewise linearized.

△U _e0 ＝k _s *(U _es -U _et ) (6)

Among them, k _s is a trace coefficient, and a smaller value is used to ensure that each iteration solution fluctuates within a smaller range.

Objective function:

min f(△X ₁ ,△X ₂ ,…Ω,△X _b+1 )＝||△U _e0 -M*△X|| (7)

Equation (53) is solved step by step iteratively to obtain △X _j , j=1, 2,...b, and the node potential U and sensitivity matrix M are updated.

X _j ＝X _j *(1+△X _j ) (9)

R” _j =R _j *X _j (10)

Iteration termination condition:

(3) PSO algorithm

The upper and lower limits of the particles are determined by the solution obtained by the deterministic algorithm, and the determined solution is used as the initial position of the first particle, and the remaining initial positions are set randomly.

The fitness function of particle i at the kth iteration:

The position and velocity update rule of particle i in the d-th dimension:

in:

When the particle touches the lower boundary, the speed and position of particle i at this moment will be updated as:

When the particle hits the upper boundary, the velocity and position of particle i are updated as follows:

When the number of iteration steps k reaches the upper limit number of steps k _max , the algorithm is terminated. At this moment, the optimal position of the particles of the entire particle swarm is output, that is, the optimal solution, and the multiplier of branch resistance obtained by the algorithm is obtained.

It should be noted that the above-mentioned ground resistance calculation and ground grid corrosion diagnosis are existing algorithms, and this application does not involve improvements to the above algorithms.

Further, the data acquisition unit 2 may adopt a single-channel voltage collector, which is mainly used for monitoring the grounding resistance of a specific equipment in a small range or diagnosing corrosion of a specific branch circuit. When aiming at the whole grounding network 4 or more electrical equipment, then adopt multi-channel voltage collector, preferably, as shown in Figure 6, data acquisition unit 2 adopts 16 road voltage collectors, and it comprises 16 data monitoring terminals and 4 A GND terminal, which can realize the collection of 16 electrical quantity signals.

Calculation evaluation unit 3 comprises: data processing module 32 and display screen 31, after data processing module 32 receives the data collected by data acquisition unit 2, obtains corresponding data by existing algorithm, and displays by display screen 31, display screen 31 can display voltage waveform, resistance value and other data.

Example 2

As shown in Figure 8, in this embodiment, the data acquisition unit 2 is adopted as a multi-channel voltage collector, the data acquisition unit 2 is integrated with the wireless transmitter, a wireless receiver is arranged at 5 in the cabinet, and the wireless receiver and the data processing module 32 connection, the data collected by the data acquisition unit 2 is sent to the wireless receiver through the wireless transmitter, and then transmitted to the data processing module 32 by wireless reception.

The above uses specific examples to illustrate the utility model, which is only used to help understand the utility model, and is not intended to limit the utility model. For those skilled in the technical field to which the utility model belongs, some simple deduction, deformation or replacement can also be made according to the idea of the utility model.

Claims (7)

1. A grounding state online monitoring device for traction power supply equipment, comprising: a data acquisition unit (2) and a calculation and evaluation unit (3), and the data acquisition unit (2) is connected to the grounding downconductor (41) and the calculation and evaluation unit respectively (3) connection, the electrical equipment under test is connected with the grounding network (4) through the grounding down conductor (41); it is characterized in that, also includes: An AC/DC excitation unit (1), the AC/DC excitation unit (1) is connected to the grounding downconductor (41), and is used to generate a DC signal or an AC current test signal different from the power frequency; When the AC/DC excitation unit generates an AC current test signal different from the power frequency, the data acquisition unit (2) is used to obtain the AC potential data of the grounding down conductor (41), and the AC potential of the grounding down conductor (41) data transmission to the computing evaluation unit (3); When the AC/DC excitation unit generates a DC signal, the data acquisition unit (2) is used to obtain the DC potential data of the grounding down conductor (41), and transmit the DC potential data of the grounding down conductor (41) to the calculation and evaluation unit ( 3); The calculation and evaluation unit (3) includes: a data processing module (32), and the data processing module (32) is connected with the data acquisition unit (2). 2. The online monitoring device for grounding state of traction power supply equipment according to claim 1, characterized in that, the AC/DC excitation unit (1) comprises: DC power supply (DC); Variable frequency alternating current power supply (AC); Dual power switch (K), connected with direct current power (DC) and variable frequency alternating current power (AC), used for power switching; The current limiting resistor (R) is connected in series with the dual power switch (K). 3. The online monitoring device for grounding state of traction power supply equipment according to claim 1, characterized in that, the calculation and evaluation unit (3) comprises: A display screen (31), connected with the data processing module (32), is used for displaying measured parameters. 4. The on-line monitoring device for grounding state of traction power supply equipment as claimed in claim 1, characterized in that, the data acquisition unit (2) is connected with the grounding network branch through a clamp (61), and is connected with the calculation and evaluation unit ( 3) Data connection. 5. The on-line monitoring device for grounding state of traction power supply equipment as claimed in claim 1, wherein said data acquisition unit (2) is a multi-channel data acquisition unit, and each channel collects the grounding down conductor potential of a branch data, the data acquisition unit (2) is wirelessly connected to the calculation and evaluation unit (3). 6. The online monitoring device for grounding state of traction power supply equipment as claimed in claim 5, characterized in that, the data acquisition unit (2) includes 16 data monitoring terminals and 4 GND terminals, which can realize the monitoring of 16 electrical quantity signals collection. 7. The on-line monitoring device for the grounding state of traction power supply equipment according to any one of claims 1-6, characterized in that it also includes a box (5), the AC/DC excitation unit (1) and the calculation and evaluation unit (3 ) is integrated in the box (5).